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Sam Hill’s World Champ’s Bike

Sneaky, Geeky Details

Words by Cam McRae. Photos by David Ferguson.
September 23rd, 2010

Sam Hill’s World Championships winning Demo 8 almost didn’t make it to Las Vegas – but things fell into place at the 11th hour.  It sat proudly next to Fabian Cancellara’s time trial machine and Alberto Contador’s Tour de France winner – covered in mud that turned out to be from Socal rather than Mont Ste. Anne.  

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  Count those cogs.  Sam Hill won on just 6 rear cogs – including two that are smaller than you and I can purchase for our bikes.

I arranged to meet my friend Jason Chamberlain at the  Specialized booth and he gave me some inside scoop on the bike.  I didn’t realize this but it turns out that Jason – the man behind much of the design and number crunching for the majority of Specialized’s dual suspension bikes – also finds time to tinker with the Specialized Monster Energy race bikes to make them lighter, faster and generally more capable.

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  This rear link plate is an interacial marriage of aluminium and magnesium.  Horseshoe-shaped linkages allow for pivots to be placed where they could not otherwise be placed because of the presence of a fat tire.

One of Jason’s projects this year was a streamlined drivetrain.  He reckoned that 9 or 10 speed was overkill and that 7 would be just fine.  He then decided that dropping down to a 9 tooth cog could bear some fruit as well – but this wouldn’t work with a conventional rear hub.  DT was enlisted to modify the free hub body to allow 9 and 10 teeth cogs to be added in place of the usual 11 speed highest gear. This higher gearing allowed for a smaller chainring as well so Jason had a custom 31 tooch ring made as well as a 30.  A smaller metal sleeve replaces the usual splined aluminum body for the first few cogs – which are machined to fit together and then mesh with the 11 tooth cog for support.

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  Specialized Engineer – and bike geek extraordinaire – Jason Chamberlain. Photo ~ Cam McRae

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  Sam and Brendan asked that the rear stays on the Demo be narrowed to allow clearance for their shoes.  Specialized obliged and now they make no contact at all.

No skipping issues have been reported despite the power generated by big engines like Sam, Brendan Fairclough and Curtis Keene. Besides adding clearance, this system saves about 200 grams when compared to an off-the-shelf top of the line drivetrain.  The larger cogs are replaced with an overshift protector that physically prevents the rear changer from moving past the largest cog.

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  The smaller rear cogs allowed for suitable top end gearing with a 31 or even a 30 tooth chainring – depending on the course.  To make this happen Jason Chamberlain had to make modifications to the bashguard and cranks and he even had to fabricate new boomerangs for the bikes.

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  Specialized founder Mike Sinyard was in the booth talking to people all day.

Jason was excited by the practical applications of a system like this for Joe rider as well.  “Imagine” he told me, ” having a 9 x 36 10-speed cassette at the rear.  Nobody would need three chainrings and most riders would have more than enough gearing with just one.”

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  SDG now makes this saddle.  Originally the Monster mechanic would take tire treads and glue them to the saddle for added grip.

Jason also walked me through some other innovations in the Demo 8 I wasn’t aware of.  There is a concentric bolt at the rear shock mount that can be rotated to increase the BB height by 10 mm (the Demo starts out an industry- lowest at 13.5″) while steepening the headtube by .75 degrees to 64.75 from 64.  The Demo also has a very short headtube because of a proprietary welding technique that allows the top of the toptube and the bottom of the downtube to connect at the upper and lower edges of the headtube with no overlap.  On most aluminum bikes the headtube must extend further to allow room for the welds.  This means that you can loosen your fork crowns and slide them up or down to tweak the head angle yet again.  Because of this you can adjust the bb height and head angle independently to a certain degree or use them in tandem to make the maximum adjustments.

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  Flush welds at the headtube junction allow for a shorter headtube, a lower front end and more adjustability.

A few other innovations on the bike include a link plate that is made of two aluminum arms bolted to a magnesium bridge, a horseshoe-shaped rear pivot mount that eliminates the rear DU bushing and allows it to pivot around an axis that runs through the rear tire, narrower rear stays to make room for Sam and Brendan’s 5:10 shoes without any rubbing and a press fit 30 bottom bracket that can accommodate almost any crank while saving 100 grams.  Aside from three titanium bolts Sam Hill’s frame is indentical to one you will be able to purchase from your local dealer.

sam hill's demo 8, 2011 world champion dh, jason chamberlain
  The Black Box BoXXers black stanchions are coated using ‘Diamond-Like Coating’ or DLC.  It’s hard (like a diamond bru!) and slippery.

Sam only uses three rotor bolts per wheel but he doubles up his rim strip with electrical tape for slightly better flat protection.  And now that we know these details each of us will be able to ride exactly like Sam and Brendan.


Want to geek out further on the bikes?  I’ll make sure your queries get back to Jason – or he may even chime in to this thread here…